PentaBorate, sodium

Boron. The principal materials used are borax [1303-96-4] sodium pentaborate, sodium tetraborate, partially dehydrated borates, boric acid [10043-35-3] and boron frits. Soil appHcation rates of boron for vegetable crops and alfalfa are usually in the range of 0.5—3 kg/hm. Lower rates are used for more sensitive crops. Both soil and foHar appHcation are practiced but soil appHcations remain effective longer. Boron toxicity is not often observed in field appHcations (see Boron compounds). 

Fig. 5. Solubility—temperature curves for boric acid, borax, sodium pentaborate, and sodium metaborate (71).

Sodium Pentaborate Pentahydrate. Sodium pentaborate pentahydrate, NaB Og -5H20 or Na20 -5B203 -10H2O formula wt, 295.11 monoclinic sp gr, 1.713 exists in nature as the mineral sborgite [12272-01 -4]. Heat capacity, entropy, and other thermal measurements have been made at 15-345 K (85). 

Crystalline sodium pentaborate pentahydrate is stable in the atmosphere. When heated in vacuum, it is stable to 75°C however, above 75°C, four of its five H2O molecules are lost (73). 

Whereas there is no commercial production of sodium pentaborate pentahydrate, the compound can be prepared by crystallizing a borax-boric acid solution having a Na20 B202 mol ratio of 0.2. 

Potassium Pentaborate Tetrahydrate. Potassium pentaborate tetrahydrate, KB Og 4H2O or K2O -5B202 8H20 formula wt, 293.20 orthorhombic prisms sp gr, 1.74 heat capacity, 329.0 J/(mol-K) [78.6 cal/(mol-K)] at 296.6 K is much less soluble than sodium pentaborate (Tables 9 and 10). Heat capacity measurements on the soHd have been made over a broad temperature range (85). 

The sohd-state stmctural formula is K[B Og(OH)4] H2O (123), which is analogous to that found ia sodium pentaborate (5). 

Sodium Calcium Pentaborate Pentahydrate. Sodium calcium pentaborate pentahydrate, NaCaB O 5H20 or Na20 2CaO 5B2O2 10H2O formula wt 351.19 monoclinic sp gr, 2.14 exists ia nature as the mineral probertite. Probertite can be prepared by heating a... 

This system is backed-up by a Standby Liquid Control System (SLCS) that injects sodium pentaborate into the moderator using a positive displacement pump (shown as a piston pump). Steam that originates in the core of a BWR, unlike the primary coolant in a PWR, exits the containment. The closing of the MSIVs isolates the radioactivity from the environment but when this is done, normal heat removal is not possible. The Residual Heat Removal (RHR) system... 

Sodium calcium pentaborate pentahydrate, 4 242t, 278-279 Sodium carbide, 22 765 Sodium carbonate, 20 631, 22 765, 787-797, 23 669, 3 416. See also Soda ash applications of, 22 794-795 from brine, 5 799-800 carbon dioxide recovery from natural gas using, 4 811... 

Sodium nitroprusside, 74 536 Sodium nonoxynol-25 sulfate cosmetic surfactant, 7 834t Sodium oleoyl isethionate cosmetic surfactant, 7 834t Sodium orthophosphates, 73 8321 Sodium orthosilicates commercial, 22 465, 466t, 469t manufacture of, 22 464, 465 Sodium oxide(s), 2 273, 22 765 in cement, 5 468 contamination by, 22 776 Sodium ozonide, 79 417 Sodium palmitate, as soap, 22 726 Sodium pentaborate... 

The pentaborate is shown by x-ray data to contain the [B506(0H)4] ion (5), analogous to that found in the sodium and potassium compounds. The a-form has the structural formula NH4[Bb06(0H)4] 2H20 and the p-form NH4[BBOg] 4H20 (126). 

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